Valve assemblies for controlling fluid flow through a valve chamber positioned between an inlet and outlet conduit and adapted for inherent correction of any misalignment that may occur between the valve component and cooperating stationary valve seat disposed in the valve chamber, or to adjust for irregularities in the valve seat itself while avoiding erosion of the valve, have been known heretofore and a variety of valve assemblies have been proposed and used for this purpose with varying degrees of effectiveness. Valve assemblies such as the foregoing providing, additionally, that the valve when closed and in abutment with the valve seat will not further rotate despite continued rotation of the valve stem are also well known for the purpose of avoiding abrasion and erosion.
The usual difficulties with known swivel assemblies, however, include sealing effectiveness, multiplicity and complexity of parts, undue cost as a consequence, vulnerability to break-down, and the substitution of equivalent erosion about the nexus of valve and valve stem for that eliminated between the valve and valve seat. A material advance in the state of the art was attained by securing to the end of a metallic valve stem a rubber seat by means of a plurality of retainer rings and incorporating a steel insert on the interior of the rubber seat to effect a swivelling adjustment of the diaphragm to any misalignment. However, this cup-like swivel component requires frequent lubrication and is not secured to the valve stem so that rotation of the valve stem does not lift the diaphragm and swivel insert from the valve seat but simply permits fluid pressure to move the diaphragm and washer upwards when the valve stem is moved away from the valve seat. A friction ring is also provided, normally, about the valve stem to provide resistance to rotation of the stem and thus a smooth functioning of the assembly rather than a sudden violent response to an abrupt rotation of the faucet handle attached to the stem. This friction ring, an O-ring normally, forms a sliding seal, as well, between the valve stem and valve housing and is subject to significant erosion and destruction in rotation of the stem to effect a linear movement thereof in the valve housing.
To obviate or reduce certain of the difficulties attendant upon the foregoing structure, an articulated valve stem was developed that permitted omission of the steel swivel insert. The stem comprises a main stem, a ball joint and foot member to accommodate any valve seat irregularity; or the like. This assembly, while providing a more effective mechanism, secures these advantages at a significant increase in size, complexity, and cost, due to material and engineering expenses. In addition, both this and the prior valve assembly include a separate stem nut and lock nut components in the valve housing.
In the event, therefore, that a swivel assembly could be constructed that would reduce the complexity and multiplicity of parts; would provide for independent rotation of the valve stem when the valve is in sealing engagement with a cooperating valve seat to eliminate erosion at the interface of the valve washer and valve seat; and do so without substituting an eroding interaction between the valve and cooperating valve stem; and, in addition, would provide for control and removal of the washer from the valve seat by direct operation of the valve stem away from the valve seat and without a dependence on the often unpredictable impact and rate of fluid flow from an inlet conduit; and would incorporate a sealing ring between the valve housing and stem that would avoid the destructive forces of slideable engagement of the sealing ring therebetween; a significant step forward in the state of the art would be secured.